Anybody have any ideas?

(Only sometimes) when using MDI or Handwheel mode and setting up our lathe with dual turrets, all of a sudden, we will notice that the X-axis is off by about 7.8 inches!!!!

That's the spacing of the two turrets and the shift caused by the G68 / G69 mirror commands.

The machine has never had a problem with X being off more than a mill or so when running parts. It only happens with user intervention during setup.

There are no jerky/violent moves and the machine always seems to do what we expect it to.

We haven't been able to correlate the occurance of the problem with specific functions, but we think it might have something to do with the machine loosing track of when to apply the X axis mirror when switching between G68 or G69 modes.

Any suggestions on how to track this down or what could be causing it?

We usually power down and back up to continue the setup process.

John